% Matt Fetterman 2005
% see M.R. Fetterman, Optics Letters 2005, improvement in derivative
% spectroscopy.
% this is the MAIN program
NumPoints=1025;displayX=1;
derivNum=1;
% time_0 is all times even...time_1 is for 1st deriv...time_2 for 2nd deriv
time_0=ones(1,NumPoints);time_0=time_0/sum(time_0);
% the FTIR_sim program returns the SNR values for the modified time, and
% the time intervals. first we try it for first deriv
[SNR_mod_1,SNR_unmod_1,time_1]=FTIR_sim(NumPoints,derivNum,displayX);
% now we try it for second deriv.
derivNum=2;
[SNR_mod_2,SNR_unmod_2,time_2]=FTIR_sim(NumPoints,derivNum,displayX);
aEnd=(NumPoints-1)/2;aStart=-aEnd;
indexer=[aStart:aEnd];
% now plot the results. large fontsizes good for display.
FontSize=16;StringFont='FontSize';
r1=plot(indexer,time_0,':',indexer,time_1,'b',indexer,time_2,'b--');
set(r1,'LineWidth',2);
ax=legend('0th derivative','1st derivative','2nd derivative');
leg=findobj(ax,'type','text');
set(leg,'FontSize',.3);
pos1=get(ax,'position');
pos2=pos1;
pos2(1)=pos2(1)-0.2;
pos2(3)=pos2(3)+0.15;
set(ax,'position',pos2);
AxisHandle=get(gcf,'CurrentAxes');
set(AxisHandle,StringFont,FontSize);
h=gcf;
xlabel('index q',StringFont,FontSize);
ylabel('time interval t(q) (seconds)',StringFont,FontSize);
% report the improvement with the technique
Noise_equal=Noise_Out(indexer,time_0,derivNum,NumPoints);
Noise_vary=Noise_Out(indexer,time_2,derivNum,NumPoints);